District Adjusts For Wet-weather Cycle

South Florida is seeing a rare convergence of extreme weather and climate phenomena that might occur at this magnitude once every 50 to 100 years, water managers said Wednesday.

Helping to fuel the combination of extremes is a slight, natural warming of the North Atlantic Ocean that could last 60 to 80 years, the South Florida Water Management District said.

For the future, that could mean, on average, more rain, more storm activity, more intense hurricanes and fewer interludes of drought, said Jayantha Obeysekera, a hydrologist, and Paul Trimble, a lead engineer for the water district.

"We have a challenge ahead of us," Trimble said.

It could mean rethinking how the 16-county agency manages the region's water resources, the water district said.

The uncommon weather has come in various manifestations, including: unusually high water in Lake Okeechobee and the Everglades, the quadruple hurricane hit Florida endured last summer, Hurricane Katrina's catastrophic assault on New Orleans, an all-time record of 71 inches of rain for the state for the 12 months that ended in July, and predictions of an extremely busy hurricane season this year.

The region entered a wetter, stormier cycle of weather about 10 years ago, a cycle not seen since the hurricane-active 1930s to 1960s, they said.

The year 1933, for instance, generated the most tropical storms on record, 21 -- the same number predicted for this year.

The shift has important ramifications for the water district, which manages water levels in Lake Okeechobee and the Everglades, removes floodwater from streets and helps keep cities supplied with drinking water.

The water district has been factoring historical rainfall data from 1965 to 2000 into its decision-making and predictive computer models.

But that now appears to have been a drier period, meaning that data alone isn't as useful for water district operations, the water district said.

"For us, we may have to change the way we do things compared to the last 30 to 40 years," Obeysekera said.

He said the water district already incorporates longer-term climate outlooks into its operations and is reflecting the transition into wetter weather into the way it manages Lake Okeechobee with the Army Corps of Engineers.

The $8.4 billion Everglades restoration project also factored in rainfall data from that drier period, but there is still time in the long-term construction project to adjust, Obeysekera said.

"We still have time to analyze the performance of those projects" with weather records that will now reach back to the 1930s to capture both wet and dry cycles, he said.

The shift to a wetter period also underscores the importance of building more reservoirs to store influxes of stormwater, Obeysekera said.

The water district has been touting its program to fast-track the construction of major water-storage depots east, west and south of Lake Okeechobee. Future runoff could be diverted to those walled-in retention areas instead of being dumped damagingly on Lake Okeechobee or the St. Lucie and Caloosahatchee Rivers.

Trimble said it is unclear when the wet cycle would end.

"They haven't reached the point where they can comfortably forecast the change from one phase to another," Trimble said.

Neil Santaniello can be reached at nsantaniello@sun-sentinel.com or 561-243-6625.